Journal of Atrial Fibrillation – Journal of Atrial Fibrillation & Electrophysiology (JAFIB-EP)

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These are curated opinions and are not peer-reviewed.

Question: What is happening in this EGM?

Why was this EGM stored?

What rhythm is observed in this recording?

Should any programming changes be considered? If so, what would they be?

Would there be any reason(s) to not reprogram anything?


This EGM was stored as a “High Ventricular Rate” episode. Nominal HVR criteria for Abbott pacemakers is 5 intervals at 175bpm. Please note the whole recording is not visible in this example, and oftentimes detection criteria is changed to 5 intervals at 150bpm.

The rhythm observed in this recording is atrial fibrillation with rapid ventricular response. The R-to-R intervals are regularly irregular.

High ventricular rate episodes are stored to capture possible ventricular tachycardia, as well as to determine
if a patient in AF is rate controlled. Closer evaluation of this recording indicates that the device is under sensing fib waves. Increasing atrial sensitivity may be an appropriate programming change to consider for this patient.

It is possible that the atrial sensitivity setting is already programmed at most sensitive. In this situation, one can
not reprogram, but could put a notation of the findings into the device in the patient’s chart. If this patient is
persistent AF, changing the permanent mode from DDDR to VVIR could be a possible consideration, especially if the device is falling in and out of AMS due to the under sensing.

One final reprogramming consideration could be beneficial if these sorts of recordings are common for this individual patient. If the physician is aware of the RVR, it is reasonable to address changing the episode storage setting to either more intervals needed to trigger an EGM, or perhaps a higher rate for HVR detection.